Salah satu faktor abiotik yang berpengaruh terhadap pertumbuhan dan kelangsungan hidup kepiting bakau adalah suhu. Media suhu yang optimum memberikan dampak pertumbuhan yang maksimum pada kepiting bakau Scylla serrata karena berkaitan dengan proses metabolisme. Penelitian ini bertujuan untuk menguji pengaruh suhu terhadap kelangsungan hidup (SR) dan laju pertumbuhan bobot harian (SGR) kepiting bakau melalui reaksi kondisi fisiologisnya. Penelitian ini terdiri dari perlakuan media bersuhu 25 °C (A), media bersuhu 27 °C (B), media bersuhu 29 °C (C), dan media bersuhu 31 °C (D). Berdasarkan hasil penelitian yang diperoleh suhu 29 °C merupakan suhu terbaik untuk pemeliharaan kepiting bakau dengan sistem resirkulasi, hal ini dapat dilihat dari hasil rasio konversi pakan, pertumbuhan spesifik dan kelangsungan hidup kepiting bakau yang memiliki nilai terbaik dibandingkan perlakuan lainnya.

Abstract. Hastuti YP, Rusmana I, Nirmala K, Affandi R, Tridesianti S. 2019. Identification and characterization of nitrifying bacteria in mud crab (Scylla serrata) recirculation aquaculture system by 16S rRNA sequencing. Biodiversitas 20: 1339-1343. Recirculation is one of the systems used for increasing aquaculture production, for example, is mud crab Scylla serrata culture. Aquaculture activities will produce organic nitrogen waste and can be affected to inorganic condition (nitrification bacteria). Nitrifying bacteria are capable of changing aerobically from NH4+ to NO2-(nitrite) and from NO2-to NO3-(nitrate). This current work aimed to identify and characterize nitrifying bacteria in mud crab (S. serrata) culture with a recirculated system. Nitrifying bacteria were isolated using serial dilution (10-1 until 10-5) of open filter FB water sample previously cultured in a specific medium. Bacterial identification was performed using a procedure of PrestoTM Mini gDNA Kit (Geneid) for DNA extraction and Polymerase Chain Reaction (PCR) primer 63F and 1387R for 16S rRNA gene amplification. Molecular identification using 16S rRNA sequences, the nitrifying bacteria isolated from mud crab recirculation aquaculture system were 99% identified as a group Pantoea calida, Pseudomonas stutzerii dan Halomonas sp. Morphological characterization of the colony morphology showed that a mucoid appearance and appeared cream in color and large size. Furthermore, their cells were recognized as basil and Gram-negative.

The availability of shelters in a specific density is expected to increase the production of mud crabs (Scylla serrata) in a recirculation system. Shelter, as one of the abiotic factors, plays a pivotal role in reducing death caused by cannibalism of crab and suppressing the stress levels of biota. Recirculation Aquaculture System (RAS), with the culture box capacity 60 L supported by the shelters, is predicted to produce the best physiological and growth responses of mud crabs. This present study aims to evaluate the effect of shelter addition in the environmental recirculation system on the physiological responses and production of mud crabs S. serrata with a density of 10 crabs per one culture box containing 60 L of seawater. The research was set up with three treatments of shelter addition, i.e., two shelters (S2), four shelters (S4), six shelters (S6), and control without shelter (C). Results showed that S6 was the best treatment with a survival rate of 73.33 ± 5.8%, a specific growth rate of 0.886 ± 0.014%, the growth rate of carapace width 0.024 ± 0.004 cm/day, and the lowest feed conversion ratio than those of other treatments. S6 treatment significantly influenced the total hemocyte count of crabs at the early cultivation (P <0.05). Addition of six shelters could optimize the growth of mud crabs with a stocking density of 10 crabs in one culture box.

Accumulation of organic matter derived from an uneaten feed, faeces, and other metabolic waste of biota can reduce water quality. This issue can be overcome by physical method using filtration systems such as malang sand. The present study aimed to identify the morphology and abundance of nitrifying and denitrifying bacteria in the mud crab Scylla serrata cultivation system treated with different weight of malang sand as i.e. 0 kg (control), 5 kg, 10 kg, 15 kg, and 20 kg. Mud crabs with the weight of 73.72±1.05 g and carapace length of 7.28±0.06 cm were reared in a container measuring 60 cm x 30 cm x 30 cm for 30 days fed two times a day using ad satiation method (as satisfied as possible). The results showed that a treatment using 5 kg malang sand was the best treatment with the survival rate of mud crabs reached 77.77±19.2%. At the end of cultivation period, nitrifying and denitrifying bacteria accounted for 1.52x107 CFU mL−1 and 1.06x107 CFU mL−1, respectively. The nitrifying and denitrifying bacteria in the rearing water were classified as Pseudomonas sp. and Acinetobacter sp., respectively.

Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis. 10 million people suffer from TB Every year. Although TB is a preventable and treatable disease, 1.5 million people die every year due to TB. Alternative treatments continue to be pursued, and treatment with the latest TB drugs that are continuously being encouraged. Black cumin (Nigella sativa) seed contains essential oils with active compounds such as thymohydroquinone, Oleoresins, flavonoids, alkaloids, saponins, tannins, and terpenoids that act as antibacterial drugs. This study aims to determine the sensitivity of  N. sativa seed extract in inhibiting the growth of  M. tuberculosis strain H37RV and MDR-TB (Multidrug Resistance-TB). This research using Microscopic-Observation and Drug-Susceptibility Assay (MODS) method. Extraction of N. sativa was carried out by the maceration method using 70% methanol as a solvent. The results showed that the M. tuberculosis strain H37RV and MDR-TB were sensitive to N. sativa extract at concentrations of 5 and 10% but resistant to N. sativa extract at concentrations of 1 and 3%.Abstrak: Tuberkulosis (TB) adalah penyakit menular yang disebabkan oleh Bakteri Mycobacterium tuberculosis. Penyakit ini menimbulkan dampak kematian yang cukup mengkhawatirkan.  Penyakit tersebut dapat dicegah dan diobati. Salah satu sumber pengobatannya menggunakan biji jintan hitam (Nigella sativa) yang mengandung minyak atsiri dengan senyawa aktif seperti timohidrokuinon, oleoresin, flavonoid, alkaloid, saponin, tanin, dan terpenoid yang berfungsi sebagai obat antibakteri. Penelitian ini bertujuan untuk mengetahui sensitivitas ekstrak biji N. sativa dalam menghambat pertumbuhan M. tuberculosis strain H37RV and MDR-TB (Multidrug-Resistance-TB). Penelitian ini menggunakan metode Microscopic-Observation and Drug-Susceptibility Assay (MODS). Ekstraksi N. sativa dilakukan dengan metode maserasi menggunakan pelarut metanol 70%. Hasil yang diperoleh menunjukkan bahwa bakteri M. tuberculosis strain H37RV dan TB-MDR, kedua  strain tsb sensitif terhadap ekstrak N. sativa konsentrasi 5 dan 10%,  tetapi resisten terhadap  ekstrak N. sativa konsentrasi 1 dan 3%.